Bioactive hydroxyapatite-sodium silicate waterglass reinforced with nanocollagen from Chitala ornata fish skin for bone engineering.

A prototype bioactive calcium phosphate model-specifically hydroxyapatite (HA) derived from eggshells-was developed using a sodium silicate (Na2SiO3) solution as an inorganic binder, precursor, and reinforcing agent, in combination with collagen nanofibers for bone engineering applications. The sodium silicate solution, functioning as a waterglass adhesive, introduced cohesive forces within the hydroxyapatite matrix, thereby enhancing its physical, chemical, and mechanical properties. Eggshell-derived bioactive hydroxyapatite offers several advantages, including non-toxicity, biocompatibility, collagen adhesion, and the ability to mimic bone structure, making it suitable for tissue engineering. To further enhance performance, the scaffold was reinforced with collagen nanofibers extracted from Chitala ornata fish skin. These nanofibers adhered effectively and integrated within the HA-Na2SiO3 matrix, improving the material's physical, mechanical, and thermal properties. The compressive strength of HA-Na2SiO3-600-Chitala COL increased significantly over 10 days, rising from 0.078 ± 0.002 MPa to 0.202 ± 0.055 MPa-an increase of approximately 2.6 times. The final composite, referred to as bioactive HA-Na2SiO3-600-Chitala COL, exhibited excellent compressive strength (1.710 ± 0.001 MPa) and strain (10.84 %) after at least 30 days of implantation. These values fall within the standard range for trabecular bone (0.1-16 MPa) and align with the interfacial characteristics of natural bone tissue. Therefore, this prototype shows strong potential for future clinical applications in bone tissue engineering.